Question

Soil water potential can be expressed as:

• A. Joule m$^{-2}$
• B. Joule kg$^{-1}$
• C. Dyne cm$^{-3}$
• D. Dyne g$^{-1}$

Hint:

Soil water potential units:
- Energy per unit mass: J/kg
- Energy per unit volume: J/m³ = Pa
- Energy per unit weight: m (head)

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Soil water potential is the energy required to move water in soil.

Step 2: Detailed Explanation:
Soil water potential is expressed as energy per unit mass.
Unit: Joule per kilogram (J/kg).
Other units:
- Pressure: Pascal (Pa) = N/m² = J/m³.
- Head: Meters (m) of water.
The energy per unit mass is the most fundamental expression.
Option A (Joule m$^{-2}$): Not a standard unit for water potential.
Option B (Joule kg$^{-1}$): Correct (energy per unit mass).
Option C (Dyne cm$^{-3}$): Not a standard unit.
Option D (Dyne g$^{-1}$): Not a standard unit.
Thus, the correct expression is Joule kg$^{-1}$.

Step 3: Final Answer:
Thus, soil water potential is expressed as Joule kg$^{-1}$.
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